An analysis of NYC's 2018 Squirrel Census

A Squirrel's World

In New York, Squirrels are everywhere. They're basically New York City's unofficial mascot (right behind Pizza rat). You see them climbing up trees, munching on acorns, terrorizing tourists, and more. As such, it only seemed right to conduct a survey of all squirrels to find all we can about our favorite cute little animal.

Thus, in the October of 2018, more than 200 volunteers descended on Central Park to conduct the 2nd most important census on American soil. Here's what they found:

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Image credits: https://www.thesquirrelcensus.com//

Comparing Fur Colors

Let’s start with a simple bar plot comparing the counts of squirrels by their fur color.

It’s obvious to us very early on that (Eastern) Gray squirrels absolutely dominate and knock the other fur colors out of the park (yes, pun intended). There’s almost as many juvenile Gray squirrels as there are Cinnamon squirrels. Such a huge gap in populations could be due to a variety of factors from genetics to environment, and more.

Image credits: https://www.pngitem.com/pimgs/b/113-1131451_squirrel-png.png//

Let’s see if there any differences come up between squirrels of different fur colors when looking at other features of our data.

Squirrel Sightings Throughout Census Period

We see that there is often variation with the squirrels seen each day, possibly due to a change in the number of volunteers each day. Still, with the information we have, time does not appear to cause any surge in any particular fur color of squirrels. The sighting numbers each day generally share the same pattern each day (look at the Gray and Cinnamon lines particularly).

The Height of Squirrels

Most of the time, the volunteers found the squirrels on the ground. There were some instances, however, where the squirrels were found looking down at the world. If the squirrel was first found above ground, their height was recorded. Maybe there is a difference in the heights squirrels are willing to go based on their fur color?

Nope. They all tend to occupy the same space in the realm above. Gray squirrels were occasionally found 50 ft (or more) above ground but that may just be that there are more Gray squirrels to find in general.

Maps of Squirrels

Above, we see every single squirrel sighting (almost 3,000) during the 2-week period of the census. (Wow, that’s a lot of squirrels)

Image credits: https://reveriechaser.com/squirrels-in-the-central-park/

We can even animate our map to show where the squirrels were found each day…

…and even by the morning or afternoon shift:

From these, we can see that Cinnamon and Black squirrels tend to be found in the same areas, which makes sense. There is strength in numbers when there’s not many of you. We can also observe that squirrels tend to not appear as much in open field areas such as ‘The Great Lawn’, ‘Sheep’s Meadow’, and ‘East Meadow.’ These areas feature almost no trees (except for on the edges) and are often filled with actual humans having picnics, playing sports, etc. which sway the squirrels away.

Next, we can actually create a density heatmap to better identify the most popular squirrel congregation areas:

The most popular area for squirrels in aggregate is ‘The Ramble’, “the most well-known of the Park’s three woodland landscapes”. With an abundance of trees and nuts here, it’s not hard to see why it’s the hottest squirrel club around.

We can separate our density heatmap by fur color too:

If you change the color to create the density map you’ll find that Black squirrels are most commonly found near ‘North Meadow’, Cinnamon squirrels near the southern border of the Park, and gray squirrels near ‘The Ramble’. From this, we’re able to identify the various areas in the Park the squirrels have carved out for themselves.

Closing Remarks

Image credits: https://2016.thesquirrelcensus.com/census.html

After all this analysis, what differences are there between Black, Cinnamon, and Gray squirrels in Central Park?

Well, not much to be honest.

These squirrels all tend to have the same behavior regardless of their fur color. They tend to congregate together in different areas of the Park but this could be just due to the instinctual need/want to be around those that look like them.

So what’s next?

We collect more data! For the 2018 Squirrel Census, it was limited to Central Park. In the most recent version of the survey (conducted in 2020), the locations were expanded to include various parks in the city. We can expand out of this further by including not only parks but various residential and commercial neighborhoods too. One can never count too many squirrels in New York City.

In the meantime, you can celebrate the 10th anniversary of the the Squirrel Census by scrolling through their twitter below:


Image Credits: Rotating ‘Squirrel Census’ Logo: https://2019.thesquirrelcensus.com/